The overall goal of this project is to study the interaction of steroid hormones with vascular tissue. Rat aorta and rat aortic smooth muscle and endothelial cells grown in tissue culture will be used to resolve the question of whether receptors for mineralcorticoids and glucocorticoids are present in vascular tissue. Experiments will be carried out to examine the effects of steroid hormones on several basic cellular functions; the phosphorylation of proteins, Na ion -K ion -ATPase activity and calcium uptake. Parallel experiments will be carried out with rats that are resistant and sensitive to mineralocorticoid hypertension. By comparing receptor characteristics, phosphorylation patterns and electrolyte disposition in each of the 2 strains, an explanation may be provided for the differences in sensitivity to mineralocorticoid hypertension.